Lighting fixtures and lighting components have been the subject of much interest in the past several years due to the inefficiency of conventional lighting solutions and the development of new lighting technologies. The incandescent light bulb and the common florescent light bulb were used for decades in lighting applications, but new lighting technologies have emerged that use less power to achieve similar light output as those conventional technologies, and they have a longer usage life. Among these are light emitting diode (LED) lighting fixtures.
LEDs are solid state electronic devices that convert electric power to light significantly more efficiently that either incandescent of florescent bulbs. However, they are driven using a direct current (DC) instead of an alternating current (AC). Accordingly, a power converter is required to convert the commercial AC service to an appropriate DC level for an LED fixture. Furthermore, a single LED requires only about one to two volts to operate, which is significantly less than the voltage supplied by commercial electrical service (e.g. 110 or 220 VAC) when rectified to a DC voltage, which can be on the order of 155 volts DC for 110 VAC service, or 311 volts DC for 220 VAC service. Converting DC at those levels down to ˜2 volts DC would result in substantial losses in the conversion circuitry.
The power conversion represents a source of inefficiency and produced heat as a result. Heat is detrimental to the operation and life of the electronic components used to control the LEDs in an LED lighting device. The conventional approach to dealing with the heat issue is to use an independent power converter that is physically separated from the LED circuitry, where power is provided over wiring to the LED fixture from the remotely located power supply. This requires the LED fixture and power supply to be packaged separately, and installed separately. The packaging, installation, sourcing and other considerations associated with having a separate power converter can add to the cost of installing LED fixtures in commercial applications. Another issue with LED lighting fixtures has been that they typically do not meet lighting output requirements for some industrial and commercial applications which are conventionally met using high power halogen and other high output light sources. Some manufacturers have tried simply grouping a high number of LEDs together in a confined area, but the heat generated by a close grouping of LEDs has tended to defeat the benefits of using LED light fixtures.
Accordingly, there is a need for a highly efficient LED lighting fixture that can meet high output lighting requirements and still maintain the power savings and long life benefits normally associated with LED lighting.
Those skilled in the field of the present disclosure will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. The details of well-known elements, structure, or processes that would be necessary to practice the embodiments, and that would be well known to those of skill in the art, are not necessarily shown and should be assumed to be present unless otherwise indicated.